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Title: Evanescent field sensors and the implementation of waveguiding nanostructures

Abstract

Conventional fiber optic evanescent-field gas sensors are based on a high number of total reflections while the gas is passing the active bare core fiber and of course a suitable laser light source. The use of miniaturized laser sources for sensitive detection of CO2 in gaseous and water-dissolved phase for environmental monitoring are studied for signal enhancing purposes. Additionally, the fiber optic sensor, consisting of a coiled bare multimode fiber core, was sensitized by an active polymer coating for the detection of explosive TNT. The implementation of ZnO waveguiding nanowires is discussed for surface and sensitivity enhancing coating of waveguiding elements, considering computational and experimental results.

Authors:
; ; ; ;
Publication Date:
OSTI Identifier:
21175987
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Optics; Journal Volume: 48; Journal Issue: 4; Other Information: DOI: 10.1364/AO.48.00B183; (c) 2009 Optical Society of America; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARBON DIOXIDE; FIBERS; LASERS; LIGHT SOURCES; POLYMERS; QUANTUM WIRES; REFLECTION; SENSITIVITY; SENSORS; SIGNALS; TNT; WATER; ZINC OXIDES

Citation Formats

Boerner, Sandra, Orghici, Rozalia, Waldvogel, Siegfried R., Willer, Ulrike, and Schade, Wolfgang. Evanescent field sensors and the implementation of waveguiding nanostructures. United States: N. p., 2009. Web. doi:10.1364/AO.48.00B183.
Boerner, Sandra, Orghici, Rozalia, Waldvogel, Siegfried R., Willer, Ulrike, & Schade, Wolfgang. Evanescent field sensors and the implementation of waveguiding nanostructures. United States. doi:10.1364/AO.48.00B183.
Boerner, Sandra, Orghici, Rozalia, Waldvogel, Siegfried R., Willer, Ulrike, and Schade, Wolfgang. Sun . "Evanescent field sensors and the implementation of waveguiding nanostructures". United States. doi:10.1364/AO.48.00B183.
@article{osti_21175987,
title = {Evanescent field sensors and the implementation of waveguiding nanostructures},
author = {Boerner, Sandra and Orghici, Rozalia and Waldvogel, Siegfried R. and Willer, Ulrike and Schade, Wolfgang},
abstractNote = {Conventional fiber optic evanescent-field gas sensors are based on a high number of total reflections while the gas is passing the active bare core fiber and of course a suitable laser light source. The use of miniaturized laser sources for sensitive detection of CO2 in gaseous and water-dissolved phase for environmental monitoring are studied for signal enhancing purposes. Additionally, the fiber optic sensor, consisting of a coiled bare multimode fiber core, was sensitized by an active polymer coating for the detection of explosive TNT. The implementation of ZnO waveguiding nanowires is discussed for surface and sensitivity enhancing coating of waveguiding elements, considering computational and experimental results.},
doi = {10.1364/AO.48.00B183},
journal = {Applied Optics},
number = 4,
volume = 48,
place = {United States},
year = {Sun Feb 01 00:00:00 EST 2009},
month = {Sun Feb 01 00:00:00 EST 2009}
}
  • A thin-film optical waveguiding evanescent dye laser was realized by an activated square-shape Rh6 G top layer on a thin-film glass waveguide. When a N/sub 2/ UV laser was focused on a diagonal line of the square dye film by a cylindrical lens, a pair of corners played a role as a corner reflecting resonator. A distinct resonance and transverse modes were observed.
  • A theoretical analysis and an experimental demonstration are presented to show the increase in collected evanescent fluorescence for a fiber-optic sensor having a high refractive-index (n{sub r}), titanium sol-gel, thin-film coating. Simulations indicated that the maximum collected fluorescence should increase and shift to smaller film thicknesses as n{sub r} increases and also predicted an interference color-filtering effect. Experimentally, collected fluorescence increased by as much as 6 over that from a bare fused-silica fiber having a numerical aperture of 0.60. Simulations and experimental data were consistent with a decrease in the effective n{sub r} as film thickness increases. Electron micrographs ofmore » the sol-gel structure supported this observation and showed that the structure differs significantly from that of films formed on a planar glass substrate. High n{sub r}, sol-gel thin films are a potentially inexpensive approach to significantly increasing the signal from fiber sensors. {copyright} 1998 Optical Society of America« less
  • Silica optical fibers have been modified to improve their sensitivity as evanescent wave sensors for liquids. A section of fiber is stripped of its cladding and bent or coiled, which significantly increases the evanescent wave interaction with the surrounding environment. The effect of sensor shape, solute concentration, refractive index, and temperature on the sensor response is discussed. {copyright} {ital 1999} {ital Society for Applied Spectroscopy}
  • Controlling the flow of photons through a fluidic media withsubwavelength optics is a major step towards the development of on-chipphotonic sensors. Central to this idea will be designing amulti-functional nanomaterial that can efficiently trap, route anddeliver light to various sensing channels, filters and detectors on aphotonic chip. Semiconductor nanowire waveguides offer an exceptionalsolution to the confinement of optical energy in solution and can bedirectly integrated into microfluidic devices. Here we demonstrate anovel optical sensing platform that utilizes the evanescent field of atin dioxide single crystalline waveguide to perform a wide array ofspectroscopic analyses including absorption, fluorescence and surfaceenhanced Raman onmore » sub-picoliter probe volumes. Since the same waveguidecavity can transmit both broadband and monochromatic light it allowsmultiple modes of detection to be carried out on the same analyte. Tomove beyond less chemical specific optical techniques such as absorptionand fluorescence we exploit the amplified electric field around silvernanocubes to enhance the vibronic signatures of molecules present in theevanescent field. With excellent chemical resilience to strong acidicconditions, the waveguides can be completely cleaned from the attachedmetal nanoparticles making the devices fully reusable. These results openup the possibility of engineering self-contained, multiplexed photonicsensors that detect and identify chemical species in complex biologicaland environmental systems.« less
  • Multi-layered chalcogenide glass waveguide structures have been fabricated for evanescent wave sensing of bio-toxins and other sensor applications. Thin films of Ge containing chalcogenides have been deposited onto Si substrates, with a-GeSe2 as the lower cladding layer and a-GeSbSe as the core layer, to form the slab waveguide. The absence of a defined upper cladding layer enhances the leakage necessary to sense the target molecules. Modal refractive index is estimated from the m-lines. It is shown that photo-induced structural changes by 808 nm laser light in the core layer selectively enhance refractive index in the exposed regions, and thus providemore » a convenient method to form channel waveguides. A thin layer of Au has been deposited on top of the core layer for the attachment of linker molecules for biosensor application; ATR confirms this.« less